1. Field of the Invention
The present invention is related to a fan with central intake and particularly to a fan frame with a fan wheel for dissipating heat in an electronic product.
2. Brief Description of the Related Art
Due to development of electronic technology, the central processor is operated with high time pulse to satisfy requirement of high executing speed. However, the central processor with high speed of data processing accompanies with much more heat generation too.
In order to dissipate the heat, it is necessary to provide a heat dissipation device. Otherwise, the central processor will be shutdown resulting from overheat if there is no excellent heat dissipation device.
Currently, the most popularly used heat dissipation device is the cooling fan because of its low cost. This is why the manufacturers are interested in developing and researching the fan.
But, the main unit of a computer provides a limited space for the fan being located so that how to promote function of heat dissipation with a fan in proper size becomes relatively significant.
Further, referring to FIGS. 1 to 4, the known fan includes a fan frame 11 and a fan wheel 12. The fan frame 11 provides a hub seat 111 with a joining part 112 at the center thereof. The joining part 112 is composed of a bearing 1121 and a spindle 1122. An inlet 113 and an outlet 114 are provided at the fan frame 11 for fluid moving in and out. The hub seat 111 is attached with a motor stator 13. The fan wheel 12 includes a hub 121 and blades 122 with a receiving part 1213 on the hub 121. A motor rotor 14 is arranged at the inner annular surface 1211 of the hub 121 and the blades 122 radially extend outward from the outer annular surface 1212 of the hub 121. The receiving part 1213 of the hub 121 is movably attached to joining part 112 of the hub seat 111 such that the rotor 14 can align with the stator 13 and the fan wheel 12 can be fitted in the fan frame.
When the stator 13 is powered on to magnetize the rotor 14, the fan wheel 12 can rotate about the joining part 12 and the blades 122 can drag the fluid to move inward via the inlet 113 and move outward via the outlet 114.
Referring to FIGS. 4 and 5, the fan frame 11 and the fan wheel 12 are mounted to the top of a radiator 16. When the fan wheel 12 rotates, the fluid is actuated to flow inward via the inlet 113 and blow toward the radiator 16 at the outlet 114 and then moves outward through air clearances 161 of the radiator 16. The problem created by the conventional fan is that the fluid does not flow toward the rear side of the hub seat 111 and a stagnation zone 15 is created at the rear side of the hub seat 111 while the fluid flows outward and disperses toward periphery of the fan frame. As a result, heat at the center of the radiator 16 is incapable of being dissipated and the heat dissipation capability becomes lowered.
Further, action between the stator 13 and the rotor 14 and rotation of the bearing 1121 are sources of heat generation, which influence heat dissipation efficiency and life span of the fan. Obviously, the conventional fan does not provide a way to discharge the heat sources and it is the reason of the conventional fan provides unfavorable effect of heat dissipation.